Arctic Gravity Project - History and Information

There is currently a great need to compile a uniform gravity grid of the Arctic region, for use in both geophysics/geology and geodesy/orbit determination. Recent advances in data collection technology, notably the advent of airborne gravimetry, the development of satellite altimetry over ice-covered regions, and availability of gravity data from scientific cruises with nuclear submarines (SCICEX), have meant that a large part of the Arctic is covered by substantial, accessible gravity field information. The ArcGP will help provide a detailed insight into the tectonics of the region, and allowing for the first time an accurate geoid model to be established. Recent presentations make it clear that monumental efforts have been made by Russia in mapping major parts of the gravity field of the Arctic Ocean, and make the formation of the ArcGP timely. The establishment of a freely available uniform gravity grid of the Arctic follows ongoing activities to develop an Arctic bathymetric map and database under the auspices of the International Hydrographic Office (IHO).

The National Imagery and Mapping Agency (NGA) has made a unique offer to lead the proposed 5 x 5 free-air and bouguer gravity grid compilations and will contribute all of its Naval Research Laboratory (NRL) airborne gravity data plus other releasable surface gravity data from its Point Gravity Anomaly file which contains over 35 million data values worldwide. NGA will be assisted by the ArcGP Special Working Group and data contributions from all organizations interested in the successful development of the project. NGA was a major collaborator with NASA/Goddard Space Flight Center and The Ohio State University on the EGM96 Geopotential Model, which was released in 1996. Information on the NASA/NGA EGM96 Geopotential Model can be found at: http://cddisa.gsfc.nasa.gov/926/egm96/egm96.html and http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm96/egm96.htm

The National Survey and Cadastre (KMS) of Denmark and NGA also jointly developed 5 x 5 free-air and bouguer anomaly maps of Greenland in 1996 using available surface gravity over land and sea, airborne gravimetry from the Greenland 1991-1992 Aerogravity Project and Digital Elevation Models (DEM) compiled by KMS. More information on the Greenland Gravity Project and the associated GEOID96A Geoid Model can be found at: http://www.kms.min.dk/